package com.airnews.ticket.util;

public class BASE64Encoder {
	private static char[] codec_table = { 'A', 'B', 'C', 'D', 'E', 'F', 'G',   
        'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',   
        'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g',   
        'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't',   
        'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6',   
        '7', '8', '9', '+', '/' };   

 public BASE64Encoder() {   

 }   

 public String encode(byte[] a) {   
     int totalBits = a.length * 8;   
     int nn = totalBits % 6;   
     int curPos = 0;// process bits   
     StringBuffer toReturn = new StringBuffer();   
     while (curPos < totalBits) {   
         int bytePos = curPos / 8;   
         switch (curPos % 8) {   
         case 0:   
             toReturn.append(codec_table[(a[bytePos] & 0xfc) >> 2]);   
             break;   
         case 2:   

             toReturn.append(codec_table[(a[bytePos] & 0x3f)]);   
             break;   
         case 4:   
             if (bytePos == a.length - 1) {   
                 toReturn   
                         .append(codec_table[((a[bytePos] & 0x0f) << 2) & 0x3f]);   
             } else {   
                 int pos = (((a[bytePos] & 0x0f) << 2) | ((a[bytePos + 1] & 0xc0) >> 6)) & 0x3f;   
                 toReturn.append(codec_table[pos]);   
             }   
             break;   
         case 6:   
             if (bytePos == a.length - 1) {   
                 toReturn   
                         .append(codec_table[((a[bytePos] & 0x03) << 4) & 0x3f]);   
             } else {   
                 int pos = (((a[bytePos] & 0x03) << 4) | ((a[bytePos + 1] & 0xf0) >> 4)) & 0x3f;   
                 toReturn.append(codec_table[pos]);   
             }   
             break;   
         default:   
             //never hanppen   
             break;   
         }   
         curPos+=6;   
     }   
     if(nn==2)   
     {   
         toReturn.append("==");   
     }   
     else if(nn==4)   
     {   
         toReturn.append("=");   
     }   
     return toReturn.toString();   

 } 
}
